Altered amplitudes of low-frequency fluctuations in primary open angle glaucoma patients: a resting-state fMRI study

To study the relationships between amplitude of low-frequency fluctuations (ALFF) changes and clinical ophthalmic parameters in patients with primary open angle glaucoma (POAG) and analyze the diagnostic value of ALFF.

Twenty-four POAG patients and 24 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging (rs-fMRI). Nonparametric rank-sum tests were used to compare the ALFF values in the slow-4 and slow-5 bands, and Spearman or Pearson correlation analysis was used to assess the correlation between ALFF changes and clinical ophthalmic parameters in POAG patients. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic performance of the ALFF.

There were 16 males in POAG patients (median age 48y) and 12 males in HCs (median age 39y). Compared with HCs, POAG patients presented increased or decreased ALFF values in different brain regions, and similar changes were observed in mild POAG patients. The ALFF values were correlated with retinal nerve fiber layer (RNFL) thickness, inner limiting membrane-retinal pigment epithelium thickness changes and the degree of visual field defects. Analysis of the diagnostic value of the ALFF via ROC curves revealed that the right medial frontal gyrus [area under the curve (AUC)=0.9063] and superior frontal gyrus (AUC=0.9097) had better diagnostic value than did the optic disc area (AUC=0.8019), visual field index (VFI%, AUC=0.8988) and macular parameters.

POAG patients present altered cortical function that is significantly correlated with the optic nerve and retinal thickness and had good diagnostic value, which may reflect the underlying neuropathological mechanism of POAG.